According to Robert T. Maleeny and William F. Palmer, Environmental Odor Control, Soap/Cosmetics/Chemical Specialties for January 1991, pp. 28-31, malodors are usually caused by chemicals that are perceived at very low concentrations. Although malodors may not be dangerous to health at low levels, they can affect one's enjoyment of the environment. Maleeny and Palmer disclose that the perfumers of ancient Egypt and Medieval Europe practised masking by deodorizing through the use of perfumes, colognes and sachets. The authors also suggested that foot care can be one of many applications for malodor counteractants.
F. Kanda et al, British Journal of Dermatology, 122, (1990), pp. 771-776 found that short-chain fatty acids, particulary iso-valeric acid, are largely responsible for foot malodour.
U.S. Pat. No. 2,973,286 discloses solvent resistant, pressure-sensitive tape adhesive coatings derived from copolymers of (a) certain monomeric acrylic acid esters of non-tertiary alkyl alcohol and (b) small proportions of certain copolymerizable monomers formed by heating the acrylate copolymers with small proportions of benzoyl peroxide or other organic peroxide soluble in the copolymer. However, U.S. Pat. No. 2,973,286 fails to suggest the use of this adhesive for the skin and in association with fragrances.
U.S. Pat. No. 4,051,159 discloses a shaped, self-supporting transparent article capable of emitting fragrance over a sustained period made of a polyamide resin formed from a polymerized fatty carboxylic acid and a polyamine, a C-14 to C-22 alkyl alcohol and a volatile essential oil.
U.S. Pat. No. 4,284,444 discloses non-porous, polymeric articles having active compounds such as antibacterial, antifungal, pesticidal, insecticidal, animal repellent, odorous, antistatic and the like, by applying to a surface of the article selected activating agents which are capable of migrating or moving throughout the body of the article to impart an effective level of activity throughout the article and/or on a surface other than the one to which the activating agents have been applied.
U.S. Pat. No. 4,419,396 discloses a three-dimensional perfumed seal made of a vinyl base sheet, an adhesive layer applied to one surface of the base sheet, a relese paper applied to the surface of the adhesive layer opposite from the base sheet, a foam synthetic resin padding material disposed on the surface of the base sheet opposite from the the adhesive layer, a covering vinyl sheet sandwiching ther padding material in cooperation with the base sheet and having a design printed on one of the opposite surfaces, and a capsulated perfume layer laminated to the covering vinyl sheet at the area where the design is present.
U.S. Pat. No. 4,493,869 discloses a flexible substrate which is transparent or translucent and which has on one surface a coating made of a binder resin having rupturable microcapsules dispersed therein and on the other surface a pressure sensitive or water-activated adhesive. The microcapsules can contain fragrances.
U.S. Pat. No. 4,605,592 and European Patent Application 103,407 disclose a multilayer decorative article having in order, an ink receptive vinyl film layer, a plasticizer barrier layer, and a pressure-sensitive adhesive layer, the adhesive layer being adapted to maintain adhesion to highly plasticized vinyl substrates, and the intermediate barrier layer being capable of preventing plasticizer from migrating from the vinyl substrate into the vinyl film outer layer.
PCT International Publication No. WO 79/01013 discloses pressure-sensitive tape adhesive made of a copolymer of alkyl acrylate and copolymerizable acid such as acrylic acid, which adhesive includes a small amount of Cr.sup.3+ ion which crosslinks the acid groups, giving the adhesive good electrical insulating properties.
U.S. Pat. Nos. 4,654,256, 4,774,133 and 4,898,663 disclose articles comprising a thermoplastic substrate bearing rupturable, fragrance-containing microcapsules in a binder on at least one surface thereof.
U.S. Pat. Nos 4,696,844 and 4,720,409 disclose a replaceable, film type air freshener primarily for use on the tiled wall of a bathroom or kitchen in which the film is constituted by a polymeric matrix having myriad cells dispersed therein impregnated with a volatile fragrance which is slowly released from the film into the atmosphere of the room.
U.S. Pat. Nos. 4,714,655 discloses a heat-sensitive material in a pressure-sensitive-adhesive matrix formed by ultraviolet and/or EB radiation, the rate of release of which can be controlled by the degree of crosslinking employed, in which the functioning of the retainined heat-sensitive material is determined by release from the pressure-sensitive-adhesive matrix at a controlled rate, of ointments containing materials such as menthols, drugs, muscle painkillers, insect repellants or fragrances.
U.S. Pat. No. 4,735,010 discloses a scent distributing device attached to footwear, including a scent source and a tubular body.
U.S. Pat. No. 4,737,410 discloses pressure-sensitive adhesives made of blends of acrylate copolymer compositions with polylyalkyloxazolines.
U.S. Pat. Nos. 4,710,536 and 4,749,590 and European Patent Application 213,737 disclose the incorporation of hydrophobic silica into acrylic pressure-sensitive adhesive tape to improve shear strength.
U.S. Pat. No. 4,814,212 discloses a repaceable air freshener unit adapted to be adhered to an automobile window to suffuse the interior of the vehicle with a pleasing or stimulating aroma.
U.S. Pat. No. 4,874,129 discloses a multi-laminate fragrance sustained release devise for releasing fragrances, colognes and perfumes at a controlled rate having a first layer of a pressure sensitive adhesive release liner for providing a protective peel strip for the device, a second layer of a silicone pressure sensitive adhesive for adhering the device to a substrate to which it is applied including human skin, a third layer of a fragrance oil impregnated matrix of a silicone material selected from the group consisting of silicone elastomers, silicone elastomers having adhesive characteristics and elastomeric silicone pressure sensitive adhesives, and a fourth layer of a permeable facestock backing member on the surface of the device for controlling the rate of release of the fragrance oil from the impregnated matrix.
U.S. Pat. No. 4,880,690 discloses perfume-emitting article or perfume patch including a fragrance-emitting layer or member comprising a fragrance oil dispersed within an ultra-thin polyurethane membrane which may be on a support.
U.S. Pat. No. 4,889,755 discloses microencapsulated materials on a strip provided between two sheet surfaces such that upon removal of the strip from between the two surfaces, some capsules rupture, releasing material contained therein.
U.S. Pat. No. 4,943,461 discloses a photopolymerized pressure-sensitive adhesive which adheres well to all common surfaces and is capable of bonding to plasticized vinyl substrates comprising an acrylic copolymer and a nitrile butadiene rubber or mixture of rubbers.
U.S. Pat. No. 4,959,208 discloses an active agent delivery device comprising (a) microporous material comprising a matrix consisting of linear ultrahigh molecular weight polyolefin, a large porportion of finely divided water-insoluble filler of which at least about 50 percent by weight is siliceous and interconnecting pores; and (b) a releasable active agent or precursor thereof associated with at least a portion of the filler.
PCT International Application WO 89/07429 discloses a printed transdermal drug delivery device made of a backing layer, an anchor adhesive layer, a layer of a pressure-sensitive pharmaceutically acceptable contact adhesive layer, an adsorbent fibrous source layer and a drug dissolved in the anchor adhesive layer or the pressure-sensitive adhesive layer.
In an AWEAR.RTM. product specifications sheet by Thermedics Inc., 470 Wildwood Street, P.O. Box 2999, Woburn, Mass., 2 pages, is described wearable self-adhesive patches which contain essential oils which are released by heat from the skin. The patches contain acrylic adhesive with a peel adhesion of 2.0 lb @ 180.degree., a barrier layer of clear polyolefin film and a fragrance containing layer made of polyurethane.
Despite the extensive research in materials research, the art fails to teach a patch which can mask foot and shoe odors through controlled release of fragrance and still remain securely attached to the foot for at least 8 hours, or to the shoe for at least 24 hours to one week. Nor are any commercially available perfume patches known which can attach to the foot or shoe and can meet the above requirements. Part of the problem lies in the relatively high loading of fragrance in the patch (i.e. about 10 milligrams (mg) or greater) necessary to mask the foot and shoe odors. Such concentrated loadings of fragrance in the patch can cause the patch adhesive to soften, causing the patch to loosen from the skin or footwear. In view of the foregoing, it would be desirable to provide a convenient patch for masking foot and shoe odors and which would be easy to apply and remove, but would remain securely attached to the foot or shoe.